Backpack



FIG. 1 is a top, front, right side perspective view of the backpack;

FIG. 2 front elevational view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a back perspective view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof; and,

FIG. 8 is a bottom, rear, and right side perspective view thereof.

The dot-dash-dot broken lines shown in the drawings are for illustrative purposes only and form no part of the claimed design. The dash-dash-dash broken lines shown in the drawings represent stitching lines. The cross-hatched lines shown in the drawings represent a textured, fabric surface. The triangular shapes shown on the bottom surface represent a contrasting textured surface. 

The ornamental design for a backpack, as shown and described. 